The inventive subject matter relates to uninterruptible power supply (UPS) systems and, more particularly, to modular UPS systems.
UPS systems are commonly used in installations such as data centers, medical centers and industrial facilities. UPS systems may be used in such installations to provide backup power to maintain operation in event of failure of the primary utility supply. These UPS systems commonly have an “on-line” configuration including a rectifier and inverter coupled by a DC link that is also coupled to an auxiliary power source, such as a battery, fuel cell or other energy storage device. Other UPS systems may use standby, line-interactive or other circuit topologies.
UPS systems may include one or more modular UPS assemblies. Each assembly may include multiple UPS modules, each of which may include, for example, a rectifier, an inverter and a DC/DC converter for interfacing to a battery. The UPS modules may be mounted in a common chassis, along with control and interface circuitry, such as bypass switches and the like. The UPS modules commonly are designed to operate in parallel to provide scalable power capacity, e.g., the modules may be coupled in common to an AC source, a DC source (e.g., a battery) and/or a load. An example of a modular UPS assembly is the Eaton® Power XPert 9395 UPS described at powerquality.eaton.com.
In large scale applications, such as data centers, multiple ones of such UPS assemblies are often individually mounted and wired to a central paralleling system using external conduits or wiring trays. Such arrangements may be expensive and time-consuming to install and difficult to expand.